Went to get my 1991 pontiac firebird 3.1l smogged yesterday everything passed except except my CO% at 15mph at .20 points shy. rich fuel mixture is the problem and i dont think enough air is getting through so Im changing the filter today going back and seeing what happens. It passed at 25mph just fine but at 15mph it was way over.

The guy said he dosen't think its my catalytic converter but was saying if i gapped the spark plugs when i re did the intake manifold which i didnt. Would the gap make a difference? Been llooking through the manual and can find the specification for the gap.. so if anyone knows the correct gap let me know.

Also any idea to help me pass smog on this car would help.. thanks

 

The correct spark plug gap is listed on the emission sticker that's applied to either the hood or radiator support.